Party-telephone-line apparatus



(No Model.) r

r A. s. HIBBARD.

PARTY TELEPHONE LINE APPARATUS.

No. 555,725. I I Patented Mar. 3, 1896.

ANDREW B.GRANAM. PHOYO-LITNQWASHINGTOKDC.

UNIT D STATES PATENT OFFIC ANGUS IIIBBARD, OF CHICAGO, ILLINOIS.

PARTY-TELE PHONE-LINE APPARATUS.

SPECIFICATION forming part of Letters Patent No. 555,725, dated March 3,1896.

Application filed September 16, 1895. Serial No. 562,614. (No model.)

To all whom it may concern.-

Be it known that I, ANGUS S. HIBBARD, a citizen of the United States,residing at Chicago, in' the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Party-Telephone-LineApparatus, (Case No. 6,) of which thefollowing isafull, clear, concise,and exact description, reference being had to the accompanying drawings,forming a part of this specification.

My invention relates to a party telephoneline with non-interferingbells.

The object of my invention is to provide means whereby a number oftelephone sets may be connected with a party-line and selective signalssent over the line to ring the bell at any one of the substationswithout affecting the remaining bells.

As employed in practice, I connect the transmitters and receivers at theseveralsub stations between the two limbs of the metallic-circuit partytelephone-line. A bell or call device is provided at each of thesub-stations, the bells at two of the sub-stations being connectedbetween one limb of the metallic circuit and ground, one of the bellsbeing adapted to respond to currents sent over the line in onedirection, while the other bell is adapted to respond to currents sentover the line in the opposite direction. The bells at the other twostations are connected between the opposite limb of the metallic circuitand ground, one of the bells being constructed to respond to currentssent over the line in one direction, while the other bell is c011-structed to respond to currents sent over the linein the oppositedirection. At the central station are provided two generators or sourcesof electricity, one adapted to send current over either of the limbs ofthe metallic circuit and ground in one direction and the other adaptedto send current in the opposite direction. Keys are provided upon theoperators switchboard, one corresponding to each of the substationsconnected with the party line, whereby when depressed the key serves toconnect one of the generators into circuit to direct current over theproper limb and in the proper direction to ring the bell of thesubscriber whose key is depressed.

Instead of providing the bells between the metallic limbs and ground,one pair of bells may be connected between one of the metallic limbs andground, while the other pair of bells maybe connected directly acrossthe two metallic limbs.

The party telephone line as thus constructed in accordance with myinvention is adapted for any number of sub-stations up to and includingfour. lhe sub stations are preferably given numbers ending in 1, 2, 3,and 4such as 51, 52, 53, and 54, 61, 62, 63, and 6 L, &c.the operatorskeysbeing numbered 1, 2, 3, and 4, whereby when the operators ringingset is connected with any particular party-line the depression of akeywill ring the bell of a subscriber whose number ends in the numbercorresponding to the number of the key.

Referring to the accompanying drawings, Figure l is a diagrammatic viewof a telephone system constructed after the manner of my invention. Fig.2 is a similar view of a modification thereof.

Like letters refer to like parts in both figures.

The limbs a a of the party telephone-line extend to the severalsub-stations, and the transmitters b b and receivers c o are connectedbetween the metallic limbs a a, the receiver being adapted when hungupon its hook to open the circuit and thus cut the telephone-instrumentsout of circuit in the usual manner.

At sub-stations A and B are provided bells or call devices d (1respectively, the bells being connected between the limb a and ground.One of the bells, d, is polarized to respond to currents sent over theline in one direction that is, for instance, to current sent from thecentral station over the metallic circuit with ground return. Theotherbell, d, is polarized to respond to current sent over the line inthe opposite directionthat is, say, from central station to ground andwith return over the limb a. At sub-stations C and D are provided bellse e, the bells being connected between the limb a and ground. One of thebells, e, is adapted to respond to current sent over the line in onedirection,while the other bell, e, is adapted to respond to current sentover the line in the opposite direction.

The limbs a a of the telephone-line terminate in the usual spring-jack fat the central station, which, in this instance, comprises springs f fwith which the terminals of a plug g are adapted to make contact whenthe plug is inserted in the spring-jack. The opposite member 9 of thepair of plugs is adapted to be inserted into the spring-jack of anothertelephone-line to thus loop two telephonelines together forconversation. The operators ringing-in key and telephone set have beenomitted from the drawings for clearness, but they may be of the usualconstruction. In the operators cord set are provided four keys h klm,which for readyidentification are preferably numbered 1, 2, 3, and 4.The keys are provided with contact-springs 7t 7t Z m respectively,normally resting against contacts h 7.3 Z 071* respectively, the springsand 0011- tacts being connected in circuit with one of the strands g ofthe cord set. The keys are also provided with springs Its t mrespectively, normally resting against contacts 7L4 7c 1 m"respectively, the springs and contacts being connected in circuit withthe strand 9 of the cord set. A grounded generator 0 is connected with acontact 7L5 upon the key 71, with which the spring h is adapted toengage when the key is depressed, and also with a contact I, with whichthe spring Z is adapted toengage when the key Zis depressed. A secondgenerator 1) is provided at the central station having one polegrounded, the grounded pole being the one opposite to that grounded inthe generator 0. The generator 19 is connected with a contact againstwhich the spring 7; is adapted to be moved when the key It is depressed,and with a contact m with which the spring m is adapted to engage whenthe key m is depressed. Upon the several keys are provided contacts h kl m respectively, which are connected to ground, the contacts beingadapted to be engaged by the springs h k Z m of the several keys whenthe respective keys are depressed.

Vhen it is desired to ring the bell at substation A the key No. 1 isdepressed, thus closing the circuit of generator 0 through contact 7L5,spring h, strand plug g, spring f limb a, bell d to ground and back tothe generator. A portion of the current also passes through bell d toground, but as this bell is polarized to respond to currents intheopposite direction only it remains irresponsive. Should it be desired toring the bell. at substation B, key No. 2 is depressed, thus closing thecircuit of generator 1) to ground through the bell (Z to limb a, springfplug g, strand g spring h, contact 7L2, spring 70, contact 70 and backto generator 1]. Should it be desired to ring the bell at sub-station 0,key N o. 3 is depressed,while if it is desired to ring the bell atsub-station D key No. 4 is depressed.

When the key h, for instance, is depressed to connect the generator 0 incircuit with the limb a and ring the hell (I, the spring 7L3 is broughtinto engagement with grounded contact h, thus grounding the strand andthe limb of and preventing the accidental ringing of the bell a, should,for instance, one of the telephone-receivers be removed from its hookand a path thus provided to the limb to. The current thus finds a shortpath to ground over the limb a, strand 9 and grounded spring h, andsuilicient current will, therefore, not pass through the bell c to ringthe same.

In Fig. 2 I have illustrated diagrammatically the manner in which onepair of bells c e, for instance, may be connected between the metalliclimbs a a, akey No. 3 being provided which when depressed sends acurrent over the metallic limbs in one direction to ring the belle,while when the key No. i is depressed current is sent over the metalliccircuit in the opposite direction to ring the bell e. \Vhen key No. 1 isdepressed current is sent over the grounded circuit in one direction toring the bell (1, while when key No. 2 is depressed current is sent overthe grounded circuit in the opposite direction to ring the bell d.

It will be noted that three conductors extend from the central stationto the sub-sta tionsthat is, the two metallic limbs a a and ground-onepair of oppositely-polarized call devices being connected between onepair of conductors, while the second pair of oppositely-polarized calldevices is connected between a second pair of conductors. In thearrangement shown in Fig. 1 the ground is common to bothcalling-circuits, while in the arrangement shown in Fig. 2 the limb a iscommon to both calling-circuits.

Instead of providing four keys in each cord set, a single set of keysmay be provided adapted to be connected with any particular pair of cordconductors that may be for the time in use.

Having described my invention, what I claim as new, and desire to secureby Letters Patent, is

In a party telephone-line, the combination with two metallic limbsextending from the central station through four substations, of atelephone set at each of said sub-stations connected in a normally-openbridge extending between the two metallic limbs, whereby the telephoneset at any one of the sub-stations may be individually connected betweenthe metallic limbs, a call device at each of said sub-stations, two ofsaid call devices being oppositely polarized and connected between oneof said metallic limbs and ground, the remaining two call devices beingoppositely polarized and connected between the other metallic limb andground, two generators at the central station, one having the positivepole grounded, the other having the negative pole grounded, two keysconnected with one of said generators, one key constructed to connectthe generator in circuit with one of the metallic limbs and the otherIIO to connect the generator in circuit with the other metallic limb,and tWo keys connected With the second generator, one constructed toconnect the generator with one of the metallic limbs While the other keyis constructed to connect the generator with the other metallic limb;substantially as described.

In witness whereof I hereunto subscribe my name this 13th day ofSeptember, A. D.

ANGUS S. HIBBARD. Witnesses GEORGE P. BARTON, W. CLYDE J ONES.

